Social isolation has a negative impact on brain health

As previously known, prolonged social isolation has negative consequences on human behavior as we are social animals. A new study supports this assertion.

Moriel Zelikowsky, et al., publish a study in the journal “Cell” in which they demonstrate how prolonged social isolation leads to a range of behavioral changes in rodents, including increased aggression, fear, and heightened sensitivity to threatening stimuli.

Prior to this study, a particular substance known as “tachykinin” had already been discovered in fruit flies, which promotes aggression in socially isolated flies. This substance binds to specific receptors on neurons, influencing the function of neural circuits.

Subsequently, it was found that this substance was not exclusive to insects but is also present in mice. The tachykinin gene (Tac2) in mice produces “neurokinin B” (NkB), a substance found in neurons in the cerebral amygdala and the hypothalamus, brain regions involved in emotional and social behavior. These scientists demonstrated how chronic social isolation led to an increase in the expression of this gene and this substance in the brain. They also found that when mice were administered a substance that blocks “neurokinin B,” their behavior returned to normal.

Conversely, if the production of this neurokinin was increased, the animals became distressed and isolated. Humans also have a similar Tac2 system in the brain, so this discovery in rodents could have potential implications for understanding how chronic isolation and stress affect human behavior.